Low-profile socketed packaging system with land-grid array and thermally conductive slug

ABSTRACT

A socketed integrated circuit packaging system, including a packaged integrated circuit and a socket therefor, is disclosed. The integrated circuit package includes a device circuit board to which a thermally conductive slug is mounted; the underside of the device circuit board has a plurality of lands arranged in an array. The integrated circuit chip is mounted to the slug, through a hole in the device circuit board, and is wire-bonded to the device circuit board and thus to the lands on the underside. The socket is a molded frame, having a hole therethrough to receive the conductive slug of the integrated circuit package; the socket may also have its own thermally conductive slug disposed within the hole of the frame. The socket has spring contact members at locations matching the location of the lands on the device circuit board. The integrated circuit package may be inserted into the socket frame, held there by a metal or molded clip. A low profile, low cost, and high thermal conductivity package and socket combination, is thus produced.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a file wrapper continuation of U.S. patentapplication Ser. No. 08/440,367, filed May 12, 1995, now abandoned.

This invention is in the field of integrated circuits, and is moreparticularly directed to packages therefor.

BACKGROUND OF THE INVENTION

Modern microprocessor-based data processing systems, particularlypersonal computers and computer workstations, are commonly upgradable inperformance and capability. Typically, this upgrading is performed byreplacing the originally installed microprocessor that serves as thecentral processing unit with a higher performance or more capablemicroprocessor. For example, one may upgrade a 386-based personalcomputer by removing the originally installed 386-type microprocessorand inserting, in its place, a 486-type microprocessor; by way offurther example, one may upgrade the central processing unit byreplacing the originally installed microprocessor with a microprocessorof the same type (e.g., 486-type) that can operate at a faster clockrate. Of course, other simple and minor adjustments of certain settingsin the computer may also need to be made to accommodate the upgradedcentral processing unit.

Therefore, in the manufacture of upgradable personal computers, certainintegrated circuits (e.g., at least the microprocessor) are installedinto the system circuit board by way of sockets, rather than by beingsoldered directly to the circuit board, to facilitate removal andreinstallation of these components. Conventional sockets include socketsof the type that apply a mechanical force to pins of the integratedcircuits so as to make contact thereto. However, as the number ofterminals for microprocessors increase to more than 150 terminals, thetotal friction encountered in removing the microprocessor from suchsockets becomes substantial, and may require a removal force of suchmagnitude as to crack or otherwise damage the board. Whilezero-insertion force sockets are also well known in the art, thesesockets are generally quite expensive.

In addition, it is of course desirable to manufacture circuit boardswith low-profile components, so that the overall height of the circuitboard and its components is relatively low. This allows for the size ofthe overall system to be quite small, which is especially important forportable personal computers, such as those of the popular notebook size.However, conventional sockets, such as those described above,significantly raise the height of the circuit board and its components.The system designer and user are thus faced with the choice betweenreduced system size and upgradability in these circumstances.

By way of further background, ball-grid array (BGA) packages have becomepopular in the art, particularly for packaging microprocessors. As iswell known, the terminals of a BGA package are solder balls, formed onthe underside of the package and attached to plated lands thereat. Asolder reflow process is then used to attach the BGA component to acircuit board after its placement thereat; the heat of the reflowprocess melts the solder balls so that they will wet to lands on thecircuit board, thus electrically and mechanically connecting thecomponent thereto. The solder reflow process is especially useful as itcan be done at relatively low temperatures, and the ability tosurface-mount the EGA packaged component eliminates the requirement ofplated-through holes in the system circuit board. In addition, EGApackages allow a large number of terminals to occupy a small board area,as the pitch of solder balls on the package can be quite small (e.g., onthe order of 0.1 cm). The BGA package is also a very low profilepackage, and is thus especially suitable for small systems such asnotebook-size personal computers and the like.

However, according to the current state of the art, the benefits of BGApackages are not available if the component is to be installed by way ofa socket. Firstly, the low profile provided by the BGA package is lost,for the most part, when the height of the socket is to be added to thesystem. Secondly, the solder balls tend to provide poor performance as amechanical connection (i.e., when not reflowed to provide a solderconnection). This is because conventional solder compositions tend tomigrate, or creep, under mechanical force. In addition, the mechanicalforce required to make electrical contact to a cold solder ball is quitehigh (e.g., on the order of one ounce), exacerbating the problem ofsolder creep under mechanical stress. This high contact force isrequired in order to overcome the native oxide that rapidly forms overthe surface of conventional solder balls. Despite these barriers,sockets for making removable connection to solder balls on a BGA packageare known in the art, as will now be described relative to certainexamples.

FIG. 1a and 1b illustrate a first example of a conventional socket forBGA components, such as is available from Methode Electronics, Inc. Inthis example, referring to FIG. 1a, BGA package 2 is converted into apin-grid-array package (PGA), by reflow soldering of the BGA package 2to pin board 4. As shown in the cross-section of FIG. 1b, pin board 4solder connects each solder ball 3 of BGA package 2 to a correspondingpin 5 extending through pin board 4. The combination of BGA package 2and pin board 4, so assembled, acts as a PGA package, and may now beinserted into conventional socket 6 that is soldered to the surface ofsystem circuit board 8. As shown in detail in FIG. 1b, each of pins 5 ofpin board 4 extend into and are received by pin sockets 7 in socket 6.Pin sockets 7 are each soldered to system circuit board 8, by way ofsolder joints 9 as shown in FIG. 1b. However, as is evident from FIG.1b, the presence of both socket 6 and pin board 4, along with the heightof reflowed solder balls 3, result in a relatively high profilecombination package system. Furthermore, the cost of this package systemcan be quite high, considering that two additional piece parts (pinboard 4 and socket 6) are required.

Referring now to FIGS. 2a and 2b, another example of a conventionalsocketing arrangement for a BGA package, manufactured and sold by AMP,will now be described for purposes of further background. As shown inFIG. 2b in cross-section, BGA package 12 has solder balls 13 connectedthereto, extending from the bottom surface thereof. Solder balls 13 arereceived by receptacles 16 in socket 14, which in turn is soldered tosystem circuit board 18 by way of solder joints 19. Referring to theplan view of FIG. 2b, receptacles 16 are, in this example, configured aspartially split rings, so that burrs 17 are present on the innerdiameter of receptacles 16. Burrs 17 serve to cut into solder balls 13when BGA package 12 is installed over socket 14, and thus provide bothmechanical support and also electrical connection between circuit board18 and solder balls 13. However, this socketing approach requires asocket thickness of at least the height of solder balls 13 (in theircold, non-reflowed state), and also suffers from the difficulties ofhigh contact force and solder creeping under stress to which cold solderconnections are vulnerable, as noted above.

By way of further background, it is known to make removable mechanicalconnection between integrated circuits having solder balls disposedthereon (e.g., according to the well-known "flip chip" technology) andcopper pads having plated palladium dendrites formed thereon. Thisapproach is believed to be used in connection with hybrid, ormulti-chip, modules, where replacement of faulty integrated circuitchips is desired. In this example, the solder balls are mechanicallyforced onto the dendrites, which serve to grip the solder ball andmechanically hold the chip in place, as well as provide electricalconnection thereto. Again, the difficulties associated with high contactforce and creeping of the solder material are also believed to bepresent in this approach.

It is therefore an object of the present invention to provide a low costsocketed package and socket system which provides a low profilecomponent placement on the system circuit board.

It is a further object of the present invention to provide such a systemwhich provides low contact force for electrical connection.

It is a further object of the present invention to provide such a systemwhich provides high density placement of terminals of the integratedcircuit.

It is a further object of the present invention to provide such a systemin which a high thermal conductivity path between the integrated circuitchip and the system circuit board is provided.

Other objects and advantages of the present invention will be apparentto those of ordinary skill in the art having reference to the followingspecification together with its drawings.

SUMMARY OF THE INVENTION

The invention may be implemented in a "land-grid-array" integratedcircuit package and socket system. An integrated circuit chip is mountedupon a thermally conductive slug and is electrically connected to adevice circuit board; a transfer-molded plastic encapsulant is locatedover the chip and bond locations on the device circuit board, forenvironmental protection. The underside of the device circuit boardsurrounding the thermally conductive slug has a plurality of platedlands, each connected to the integrated circuit chip therewith. Thesocket is formed of molded plastic, and has an arrangement of springelements extending therethrough that are arranged to correspond to theplated lands on the underside of the device circuit board. Surfacemounting technology is used to solder the socket to the system circuitboard, allowing the land-grid-array package to be inserted and removedfrom the socket without soldering. A clip is provided to secure theland-grid-array package within the socket. Alternative techniques areutilized for thermal conduction between the thermally conductive slug inthe land-grid-array package and the system circuit board.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a and 1b are exploded perspective and partial cross-sectionalviews, respectively, of a ball-grid-array socketing system according tothe prior art.

FIGS. 2a and 2b are cross-sectional and partial plan views,respectively, of another ball-grid-array socketing system according tothe prior art.

FIGS. 3a, 3b, and 3c are plan, cross-sectional, and underside views of aland-grid-array integrated circuit package used in the preferredembodiment of the invention.

FIGS. 4 and 5 are plan and cross-sectional views, respectively, of thesocket used in the preferred embodiment of the invention.

FIGS. 6a and 6b are plan and cross-sectional views, respectively, ofholes in the socket of FIGS. 4 and 5, and illustrating the position ofspring contact elements therein.

FIG. 7 is a cross-sectional view of the preferred embodiment of theinvention, illustrating the land-grid array package inserted into thesocket and the socket mounted to a system circuit board.

FIG. 8 is a cross-sectional view of an alternative embodiment of theinvention, illustrating the land-grid array package inserted into thesocket.

FIGS. 9a and 9b are cross-section and plan views, respectively, of holesin the socket according to an alternative embodiment of the invention,incorporating coil spring contact elements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

According to the preferred embodiment of the invention, a system isprovided that includes a low-profile integrated circuit package and asocket for removably retaining the same. This advantageous system thusallows for the system manufacturer to mount the socket onto the systemcircuit board, and to thereafter insert the integrated circuit packageinto the socket. Removal and replacement of the integrated circuitpackage is thus facilitated by the present invention, while retainingthe low-profile form factor of the mounted component and socket system.It is further contemplated that the electrical connection between theintegrated circuit package and the system circuit board, through thesocket, will be superior in quality and reliability to conventionalsocketing arrangements used in connection with ball-grid-array (BGA)integrated circuit packages. It is thus contemplated that the presentinvention will provide the benefits of socket installation, namely inallowing for easy non-destructive removal and replacement of theintegrated circuit chip, without incurring the difficulties presented byconventional BGA socketing approaches, while still retaining thebenefits of low package cost, low package profile, high thermalconductivity, and high density terminal placement already provided bymodern BGA package technology.

Referring now to FIGS. 3a through 3c, land-grid-array (LGA) integratedcircuit package 20 according to the preferred embodiment of theinvention will first be described in detail. FIG. 3a provides a topsideview of LGA package 20, while FIG. 3b is a cross-sectional view thereof.As shown in FIG. 3b, integrated circuit chip 25 is mounted to thermallyconductive slug 26, by way of a thermally conductive adhesive.Conductive slug 26, as will be described hereinbelow, will provide athermal conduction path between chip 25 and the system circuit board towhich the system is mounted, and as such is preferably formed of ahighly thermally conductive material such as copper. Conductive slug 26is attached on its top side not only to integrated circuit chip 25, butalso to the underside of device circuit board 22, to provide structuralsupport for chip 25 therewithin.

Device circuit board 22 is preferably formed of conventional printedcircuit board material, such as FR-4, and also preferably has aplurality of levels of interconnection therewithin to efficiently carrysignals to and from integrated circuit chip 25 without undue noiseeffects. Alternatively, device circuit board 22 may be a ceramicsubstrate, or a substrate of another composition as known in the fieldof integrated circuit packaging. Electrical connection is made betweenintegrated circuit chip 25 and device circuit board 26 by conventionaltechniques, an example of which is bond wires 27 shown in FIG. 3b,attached by conventional thermocompression wire bond technology.

FIG. 3c is a bottom-side view of LGA package 20. As shown in FIG. 3c,the central portion of which is occupied by conductive slug 26, whichextends below the surface of device circuit board 22 (FIG. 3b). An arrayof plated lands 30 are located on the bottom-side of device circuitboard 22, occupying a plurality of rows of connections (e.g., two suchrows, as shown in FIG. 3b). Lands 30 are preferably gold-plated lands,to provide for maximum electrical conductivity and minimum requiredmechanical contact force.

LGA package 20 of FIGS. 3a through 3c thus substantially resembles aconventional ball-grid-array (BGA) package, except that no solder ballsare provided on the underside of device circuit board 22 in connectionwith lands 30. It is also contemplated that the size of lands 30 of LGApackage 20 may be slightly larger than the size of corresponding landsfor solder balls in conventional BGA packages; for example, the lands ofconventional BGA packages are typically on the order of 0.6 mm indiameter, while lands 30 in LGA package 20 may have a diameter ofapproximately 1.0 mm, for a 1.2 mm pitch package.

Referring now to FIGS. 4 and 5, the construction of socket 40, withwhich LGA package 20 mates, will now be described in detail. Socket 40is preferably fabricated of a low cost material, such as RYTON plasticavailable from Phillips Petroleum, injected molded to form the shape ofLGA package 20. According to this embodiment of the invention, socket 40is in the shape of a frame with an opening 42 therethrough, throughwhich conductive slug 26 of LGA package 20 can extend to contact asystem circuit board, as will be shown hereinbelow. Socket 40 furtherhas orientation indicator 45, which is a cosmetic structure indicatingthe corner at which a specific terminal of LGA package 20 (e.g., pin 1)is to be placed for proper electrical connection.

Socket 40 further has a plurality of holes 44 therethrough. Holes 44 arematched with the locations of lands 30 on LGA package 20, and willreceive spring contact elements that will make contact between thesystem circuit board and lands 30, as will also be shown hereinbelow.

As shown in FIGS. 4 and 5, socket 40 has snap lips 43, on opposing sidesthereof, for snapping around and holding LGA package 20 when insertedinto socket 40. Of course, the particular shape and location of snaplips 43 may be selected for the particular application, as useful forease of removal and installation. Alternatively, socket 40 may befabricated without snap lips 43, in which case a metal spring clip maybe used to secure LGA package within socket 40 after insertion. Examplesof conventional spring clips that may be so used, with slightmodification, are spring clips of the type commonly used to secure heatsinks to integrated circuit packages.

Referring now to FIGS. 6a and 6b, the construction of an example ofcontact holes 44 and spring contact element 50 according to thepreferred embodiment of the invention will now be described in detail.As shown in FIG. 6a, holes 44 are substantially of square shape, toaccommodate a spring contact element 50 inserted therethrough. In thisembodiment of the invention, as shown more clearly in FIG. 6b, socket 40includes a molded protrusion 45 extending into each of holes 44.Protrusion 45 has a flat top surface to allow the insertion of springcontact element 50 thereinto from the bottom, and a sloped bottomsurface to lock spring contact element 50 thereinto.

Spring contact element 50, in this example, is a strip of precious metalalloy having good spring properties (e.g., PALINEY alloy available fromJ. M. Ney Co., which is a palladium-silver-copper alloy) formed into theappropriate shape for insertion into and retention by hole 44; theprecious metal composition of spring contact elements 50 provideexcellent electrical conduction, as is well known. In this example, eachspring contact element 50 is formed to have a bent portion with an end51 that will rest upon the top surface of protrusion 45. An uppersurface of spring contact element 50 is formed to have a dimple 54;dimple 54 preferably has a flat top surface so as to make contact to acorresponding one of lands 30 of LGA package 20 over an area (ratherthan as a point contact). Each spring contact element 50 preferablyextends above the upper surface of socket 40, so that it is compressedby LGA package 20 when installed, thus ensuring good electrical contactto its associated land 30. Each spring contact element 50 further has aslightly angled portion 52 at its bottom, which defines, relative tohole 44 in socket 40, a small area 55 into which solder may wick andwet, thus facilitating solder mounting of socket 40 to a system circuitboard.

Spring contact elements 50 are preferably formed into the desired shapein their assembly. Spring contact elements 50 are installed into socket40 merely by inserting each into a corresponding hole 44 from the bottomsurface of socket 40, with dimple 54 leading. This technique allowsspring contact elements 50 to snap around protrusion 45 and to be heldin place thereat. Upon installation of all of spring contact elements 50into socket 40, socket 40 is then ready for solder mounting to thesystem circuit board application, as desired.

Alternatively, spring contact elements may be formed to have differentshapes from that shown in FIGS. 6a and 6b. For example, it iscontemplated that coil spring elements may be used to provide contact toLGA package 20 for socket 40. However, such coil spring elements arebelieved to provide somewhat more inductive contact both to LGA package20 (on the top side) and to the system circuit board (on the bottom),considering that the surface area of contact will be very small in thatevent. FIGS. 9a and 9b illustrate such an alternative embodiment of theinvention, in which coil spring contact elements 80 are disposed withinholes 44' of socket 40'. In this example, holes 44' are of circularcross-section, and preferably have a lower portion 44L of smallerdiameter than an upper portion 44U from which coil spring contactelements 80 protrude, resulting in a shoulder S at the change ofdiameter within holes 44'. Shoulders S provide a stop for coil springcontact elements 80 so as to maintain upward pressure on a chip package20 inserted thereabove; in addition, shoulders S allow coil springcontact elements 80 to be retained within the combination of chippackage 20 and socket 40' in the case where chip package 20 is mountedinto socket 40' prior to solder mounting socket 40' to the systemcircuit board.

Referring back to the embodiment of FIGS. 4, 5, 6a and 6b, socket 40will typically be wave soldered or subjected to solder reflow dependingupon the selected solder composition (i.e., depending upon the type ofsolder, e.g., a tin lead mixture). Alternatively, LGA package 20 may bemounted into socket 40, prior to the mounting of socket 40 to the systemcircuit board. For purposes of illustration, FIG. 7 illustrates, incross-sectional view, the mated combination of LGA package 20 and socket40 as assembled to system circuit board 33.

As shown in FIG. 7, conductive slug 26, upon which chip 25 is mounted inLGA package 20 as described hereinabove, extends through hole 42 insocket 40. The bottom surface of conductive slug 26 is thus exposed forcontact with a thermally conductive element (not shown) within systemcircuit board 33. A thermally conductive "grease" may be applied to theunderside of conductive slug 26, to provide a secure thermal pathbetween slug 26 and system circuit board 33, but still allowing removalof LGA package 20 if necessary.

As shown in FIG. 7, snap lips 43 hold LGA package 20 within socket 40.Spring contact elements 50 extend through socket 40, so as to have theirdimples 54 in contact with lands 30 in LGA package 20. The lower portionof each of spring contact elements 50 (i.e., portion 52) are wavesoldered to system circuit board 33, connected at solder joints 53.

According to this embodiment of the invention, exemplified by the systemof LGA package 20 and socket 40, many advantages are obtained. Firstly,a socketed installation of an extremely low profile integrated circuitpackage is made available, where the socket itself is of low profile.Secondly, the disadvantages of making mechanical connection to solderballs (as is done in conventional socketing arrangements for BGAdevices) are avoided, as the solder balls are not present, and becauseprecious metal spring contact elements may now be in direct contact withboth a plated land at the underside of the integrated circuit package,and by way of wave solder to the system circuit board. A low resistancecontact is thus provided. Furthermore, each of the piece parts used inthe construction of the package and socket according to the presentinvention can be of quite low cost, especially considering thefabrication of LGA package 20 with conventional printed circuit boardmaterial and without requiring the attachment of solder balls thereto.The arrangement according to this embodiment of the invention furtherprovides easy installation and removability of LGA package 20 fromsocket 40; in this example, such versatility is by virtue of snap lips43 having a sloped corner surface to permit downward force to installLGA package 20 thereinto, along with a flat undersurface that holds LGApackage 20 thereat after installation.

Referring now to FIG. 8, an alternative embodiment of the package andsocket system according to this embodiment of the invention will now bedescribed in detail. According to this embodiment of the invention,socket 60 is provided with its own thermally conductive slug 62. Slug 62is attached to the underside of plastic molded body 60 and is exposed ina central opening thereof. Preferably, socket 60 is molded with slug 62,in which case slug 62 preferably has several holes 64 therethrough intowhich mold compound flows during transfer molding to lock slug 62 to theframe of socket 60.

Also according to this embodiment of the invention, lead-grid arraypackage 20' is similarly constructed as package 20 describedhereinabove, having a conductive slug 56 that is similarly positioned asslug 26 in the above-described embodiment, but having only half thethickness. Accordingly, slug 56 becomes in contact with socket slug 62when LGA package 20' is inserted into socket 60; preferably, a thermalgrease is dispensed at the top surface of socket slug 62, to providegood thermal conduction therebetween but yet still provide ease ofseparability between LGA package 20' and socket 60 if LGA package 20' isto be removed therefrom.

Also in this embodiment of the invention, socket 60 has no snap lips.LGA package 20' is instead retained within socket 60 by way of springclip 70. Spring clip 70 provides adequate downward pressure on LGApackage 20' to ensure that spring contact elements 50 are in contactwith their associated lands (not shown), to ensure that conductive slugs56, 62 are in contact with one another, and to provide mechanicalstability. The ends of spring clip 70 are held in holes or depressionswithin the body of socket 60, as shown in FIG. 8.

This embodiment of the invention provides similar benefits as describedhereinabove, but also may allows for increased thermal conductivity fromintegrated circuit chip 25 to the system circuit board, as socket slug62 provides additional contact area to the system circuit board fromthat which may be possible for LGA package 201. Much of the low costadvantages still remain for this embodiment of the invention, as well.

Accordingly, the present invention provides for important advantages inproviding low-cost, low-profile socket installation for integratedcircuit packages, particularly modern ultra high scale integratedcircuits, such as microprocessors, that dissipate several watts of powerin operation.

While the invention has been described herein relative to its preferredembodiments, it is of course contemplated that modifications of, andalternatives to, these embodiments, such modifications and alternativesobtaining the advantages and benefits of this invention, will beapparent to those of ordinary skill in the art having reference to thisspecification and its drawings. It is contemplated that suchmodifications and alternatives are within the scope of this invention assubsequently claimed herein.

We claim:
 1. An integrated circuit package disposed in a socket, comprising:an integrated circuit package, comprising: a first thermally conductive slug; an integrated circuit chip mounted on said first thermally conductive slug; a device substrate attached to said first thermally conductive slug, said device substrate having a plurality of plated lands disposed on a bottom surface thereof; a plurality of electrical connections between said integrated circuit chip and said device substrate, and a socket comprising:a frame having a first surface and a second surface, and having an opening therethrough; a plurality of spring contact elements disposed proximate to the opening in said frame, each of said spring contact elements extending through said frame from said first surface to said second surface, and each of said spring contact elements being held in contact with a corresponding one of said plated lands; and a releasable holding means holding said integrated circuit package proximate to said frame.
 2. The integrated circuit package of claim 1 wherein said releasable holding means is formed integrally with said frame.
 3. The integrated circuit package of claim 2 wherein said releasable holding means comprises a plurality of snap lips extending from said first surface of said frame.
 4. The integrated circuit package of claim 1 wherein said releasable holding means comprises a spring clip.
 5. The integrated circuit package of claim 1 wherein each of said spring contact elements is comprised of a precious metal.
 6. The integrated circuit package of claim 1 further comprising a plurality of holes formed through said frame, one of said spring contact elements being disposed in each of said holes.
 7. The integrated circuit package of claim 6, further comprising a plurality of protrusions, each protrusion being located within one of said holes and being in contact with a respective one of said spring contact elements to hold said spring contact element in said hole.
 8. The integrated circuit package of claim 1 wherein each of said spring contact elements further comprises a dimple extending above said first surface of said frame and being in contact with a corresponding one of said plated lands.
 9. The integrated circuit package of claim 1, further comprising:a second thermally conductive slug disposed within the opening in said frame, said second thermally conductive slug being in contact with said first thermally conductive slug.
 10. The integrated circuit package of claim 1, further comprising:a layer of thermally conductive grease disposed on a bottom side of said first thermally conductive slug; an encapsulant material disposed over said integrated circuit chip; and wherein said device substrate is a device circuit board.
 11. The integrated circuit package of claim 1 wherein said spring contact elements are comprised of coil springs.
 12. An integrated circuit package disposed in a socket, comprising:an integrated circuit package, comprising: a thermally conductive slug; an integrated circuit chip mounted on said thermally conductive slug; a device substrate attached to said thermally conductive slug, said device substrate having a plurality of plated lands disposed on a bottom surface thereof; a plurality of electrical connections between said integrated circuit chip and said device substrate; and a socket comprising:a frame having a first surface and a second surface, and having an opening therethrough; a plurality of spring contact elements disposed proximate to the opening in said frame, each of said spring contact elements being held in contact with a corresponding one of said plated lands; and a releasable holding means holding said integrated circuit package proximate to said frame.
 13. The integrated circuit package of claim 12, further comprising:a layer of thermally conductive grease disposed on a bottom side of said thermally conductive slugs; an encapsulant material disposed over said integrated circuit chip; and wherein said device substrate is a device circuit board.
 14. The integrated circuit package of claim 12 wherein said spring contact elements are comprised of coil springs.
 15. An integrated circuit package disposed in a socket, comprising:a first thermally conductive slug having a first surface and a second surface; an integrated circuit chip mounted to the first surface of said first thermally conductive slug; a device substrate having a bottom surface, said device substrate being fixed to said first thermally conductive slug, the second surface of said first thermally conductive slug extending below the bottom surface of said device substrate; a plurality of electrical connections between said integrated circuit chip and said device substrate; a plurality of plated lands disposed on the bottom surface of said device substrate; a frame; a plurality of spring contact elements disposed in said frame, each of said spring contact elements extending through said frame; and a releasable holding means holding said device substrate proximate to said frame, each of said plated lands being in contact with a respective one of said spring contact elements.
 16. The integrated circuit package of claim 15, further comprising an opening formed through said frame, said first thermally conductive slug being aligned in the opening of said frame and being received therein.
 17. The integrated circuit package of claim 16, further comprising a second thermally conductive slug disposed in the opening of said frame, said second thermally conductive slug being in contact with said first thermally conductive slug.
 18. An integrated circuit package mounted on a system substrate, comprising:a first thermally conductive slug having a first surface and a second surface; an integrated circuit chip mounted to the first surface of said first thermally conductive slug; a device substrate having a bottom surface, said device substrate being fixed to said first thermally conductive slug, the second surface of said first thermally conductive slug extending below the bottom surface of said device substrate; a plurality of electrical connections between said integrated circuit chip and said device substrate; a plurality of plated lands disposed on the bottom surface of said device substrate; a frame having a first surface and a second surface, and having a plurality of holes formed therethrough; a plurality of spring contact elements, each spring contact element being disposed in one of said holes; a plurality of conductive joints formed on a system substrate, each of said conductive joints being connected to a second end of a respective one of said spring contact elements such that said frame is fixed to said system substrate; and a releasable holding means holding said device substrate proximate to said frame, each of said plated lands being in contact with a first end of a respective one of said spring contact elements such that a plurality of conductive pathways are formed, each conductive pathway comprising one of said plated lands, one of said spring contact elements, and one of said conductive joints.
 19. The integrated circuit package of claim 18, further comprising an opening formed through said frame, said first thermally conductive slug being aligned in the opening of said frame and being received therein.
 20. The integrated circuit package of claim 19 wherein said first thermally conductive slug is held in contact with said system substrate, and further comprising a layer of thermally conductive grease being disposed between said first thermally conductive slug and said system substrate.
 21. The integrated circuit package of claim 19, further comprising a second thermally conductive slug fixed in the opening in said frame, said second thermally conductive slug being held in contact with said first thermally conductive slug and said system substrate, said second thermally conductive slug being disposed between said first thermally conductive slug and said system substrate.
 22. The integrated circuit package of claim 21, further comprising:a layer of thermally conductive grease interposed between said first thermally conductive slug and said second thermally conductive slug; and a layer of thermally conductive grease interposed between said second thermally conductive slug and said system substrate.
 23. The integrated circuit package of claim 19 wherein said conductive joints are solder joints, the second end of each of said spring contact elements being connected to one of said solder joints with a solder connection, and wherein said device substrate is a device circuit board and said system substrate is a system circuit board.
 24. The integrated circuit package of claim 19, further comprising an encapsulant material disposed over said integrated circuit chip.
 25. The integrated circuit package of claim 19 wherein each of said holes further comprises a protrusion, each of said spring contact elements being held in a respective one of said holes by one of said protrusions.
 26. The integrated circuit package of claim 19 wherein said releasable holding means is formed integrally with said frame.
 27. The integrated circuit package of claim 26 wherein said releasable holding means comprises a plurality of opposing snap lips.
 28. The integrated circuit package of claim 19 wherein said releasable holding means comprises a spring clip.
 29. The integrated circuit package of claim 19 wherein the second end of each of said spring contact elements extends through the second surface of said frame and the first end of each of said spring contact elements extends through the first surface of said frame.
 30. The integrated circuit package of claim 19 wherein each spring contact element is comprised of a coil spring.
 31. The integrated circuit package of claim 19 wherein each of the spring contact elements is comprised of a precious metal and the first end of each of said spring contact elements is formed in the shape of a dimple. 